Setup

First, download the Mystery Machine code dumper and patcher from here, ctr-httpwn from here and HANS from the 3DS homebrew starter pack. Extract each to the SD card appropriately. Make sure the sdmc:/hans/ folder exists on your SD card. Next, download the following user_config.xml from here and place it at sdmc:/3ds/ctr-httpwn/user_config.xml. This will allow the HANS-patched code to access online Mystery Gift events and bypass update requirements through ctr-httpwn.

Next, run the Mystery Machine code patcher 3dsx with the game you intend to use. This will dump the game's code and patch it so that it will communicate with the Mystery Machine's servers for Mystery Gift. This only needs to be done once per game, one time only, as long as the patched .code files are in sdmc:/hans/.

Once you have your code patched, the following are the only things needed to do for each launch of Mystery Machine: First, launch ctr-httpwn and enable online functionality. Then open HANS with your game, adjust the settings to your desired region and language, and set "Code -> SD" to "YES". Additional romfs modifications can also be loaded if desired, along with higher N3DS clock speeds. Once all the settings are set properly, press "OK" to launch, and proceed to Mystery Gift.

In Mystery Gift, you have two options: Either go through the Internet gift as normal and recieve previous and current gifts, or use the Code gifts. With code gifts, you can manually select from a storehouse of archived gifts, using the BOSS ID of the gift you want to recieve. Different versions of the games may contain different gifts from each other, depending on which gifts were previously archived. For the most part, however, you can simply type the digits of the code you are downloading within the first 4 digits of the serial code. So if you wanted to download event 553 for the serial code Hoopa, you would type "0553" and press enter to fill the rest of the code with 0's. Event 12 would be "0012", 1234 would be "1234" and so on. Information on held events can be found in the FAQ section.

Credits

FAQ

Spoofing?

This code modification redirects all the servers used for serial code validation and BOSS to our own servers, which will emulate the functionality of the official servers. As a result, functionality can also be added such as the ability for the serial code input to also act as a selection for which events to download. Previous BOSS events can also be archived and still be used, since the BOSS archives are still signed and valid, despite no longer existing on Nintendo's servers. This allows (some) previous events to be replayed.